Power transmission unit



7, 1942. C. F. BALL T-AL POWER TRANSMISSION UNIT Filed Jan. 5, 1940 eSheets-Sheet 1 a Mr W/ Nov. 17, 1942. c. F. BALL ETAL POWER TRANSMISSIONUNIT 6 Sheets-Sheet 2 Filed Jan. 3, 1940 gwue/vv omy C/zarZesFLBall andLamb Iremez'er;

'c. F. BALL ETAL 2,302,515 POWER TRANSMISSION UNIT Filed Jan. 5, 1940 ssheets-sheet s Nov. 17, 1942.

Nov. 17, 19 2- c. F. BALL ETAL 2,302,515

POWER TRANSMISSION UNIT Filed Jan. 5, 1940 6 Sheets-Sheet 4 Louisafilkemeier;

Nov. 17, 19 c. F. BALL ETAL 2,302,515

POWER TRANSMISSION UNIT 7 Filed Jan. 5, 1940 6 Shets-Sheei 5 CharlesEflall and Loads afiz'lkemez'el Nov. 17, 19142. F, BALL HAL 2,302,515

POWER TRANSMISSION UNIT Filed Jan. 3, 1940 '5 Sheets-Sheet 6 3140044104ahal'lfiz'fiall an Louis Gfiilkemeier;

Patented Nov. 17, 1942 Charles F. Ball, Wauwato meier, Milwaukee, Wis,

Company, Milwaukee, Wis'.,

Wisconsin sa, and Louis G. Hilke' assignors to Chain Belt a corporationof Application January 3, 1940, Serial No. 312,286

4 Claims.

The invention relates to unitary power transmission and change speedmechanism, and has for one of its objects to provide apparatus of thischaracter in the form of an attachment which is especially applicable toconcrete mixers of the truck mounted type whereby the mixing oragitating receptacles and other instrlnnentalities appurtenant theretomay be driven from the truck motor.

Certain earlier concepts of truck mounted concrete mixers contemplatedthe driving of the mixing or agitating instrumentalities from the powerplant of the vehicle upon which the mixing unit was mounted, duringtransit of the vehicle from a central batching or mixing plant to thepoint at which the concrete was to be used, and some of the earlierforms' of truck mixers which appeared in commercial practice attemptedto make use of this principle. It was found however, that most of thepower of the truck engines of that day was required in moving thevehicle itself and its load over the ground under various operatingconditions, as a result of which there was little surplus poweravailable from this source for agitating the concrete constituentswithin the receptacles. As a consequence, until recently it has beenpractically universal truck mixer practice to use a separate orindependent engine for driving the mixing or agitating and associatedinstrumentalities, which engines were mounted and sold as a part of themixing unit. Although such additional engines of course addedappreciably to the cost of the mixing units they were neverthelessemployed to insure ample power for mixing, and they also afforded someadditional advantages in the'way of flexibility and the maintenance of aconstant mixing speed.

With recent developments in the Diesel engine field which have resultedin a rapid extension of the use of such engines in motor trucks, andwith the present day tendency to furnish even gasoline driven truckswith motors sufficiently powerful to take care of not onlytransportation requirements but also extraneous power needs, truckmounted concrete mixing o'r agitating units driven from the truck motorare again coming into use.

However, manufacturers are still prepared to furnish separate-enginedriven units if desired, and since the mixing or agitating unitsthemselves are fundamentally the same whether a separate engine or thetruck motor be employed as a source of power therefor, it is desirableto provide a relatively simple power transmission unit which may bereadily mounted on the mixed frame in the place of the separate engine,and

provide for the transmission of power from a power take-off, such as inman instances is furnished as a part of the truck equipment, to themixing and associated instrumentalities. Preferably such powertransmitting mechanism takes the form of an attachment which may bereadily substituted for the usual separate engine of the mixer oragitator without change in the more or less standardized construction ofsuch units.

In one well known standard truck mixer unit of the separate enginedriven type, the power transmission between such engine and the mixingdrum includes a reduction gearing enclosed within a housing having twocommunicating chambers in one of which the said gearing is mounted,while in the other chamber may be mounted a main clutch for controllingthe drive from the engine to the transmission. In one form of saidtransmission, as exemplified in the co-pending application of Louis G.I-lilkemeier, filed April 11, 1939, Serial No. 267,284, now Patent No.2,243,035, granted May 20, 1941, the said main clutch is omitted, and inlieu thereof two separate clutches and a reversing gearing areincorporated into the reduction gearing to provide for the driving ofthe mixer or agitator in one direction for mixing or agitating purposesand in the opposite direction for discharging purposes. The saidreversing gearing and clutches are mounted within the said reductiongear chamber of the housing, and while the main clutch chamber of thelatter is retained it is not employed, and may be effectively used toreceive and house a portion of the power transmitting attachment unitconstituting the present invention. Even where this double reversingclutch form of transmission is not employed, a main clutch to disconnectthe drive immediately preceding the reduction gearing is not necessaryin the case of a truck motor drive, and therefore such main clutchchamber is still available.

As is well known to those skilled in truck mixer practice, it iscustomary to conduct the initial mixing operation at a relatively highspeed, and after a predeterminedv period during which the constituentsof the concrete are thoroughly commingled, to then reduce the speed ofthe drum to such as will merely prevent segregation of the constituentsand maintain the mixture in workable form. The higher speed may also bedesirable for discharge purposes. In the case of the separate enginedriven mixer units, these speed changes may be readily effected by meansof the throttle on the separate engine; but with a truck motor drivenunit, such speed control is not usually available, as the speed of thetruck motor at most times depends on the speed at which the vehicle isbeing driven over the ground. It is therefore desirable in the case oftruck motor drives to provide a change speed gearing providing at leasttwo different speeds, whereby the flexibility of the separate engineunit may be approached.

In usual practice, truck mixers or agitators mix or agitate batches ofconcrete while transporting the same from a central loading station tothe location of the job, which is generally a considerable distance, andfor economy in operation the mixers or agitators are built in sizesranging i.

in capacity from one cubic yard to six cubic yards or more. Since acubic yard of wet concrete weighs in the neighborhood of two tons, thecontents of the mixing or agitating receptacles may weigh from two totwelve tons or more,

thereby throwing such a heavy load upon the entire power transmissionmechanism of the unit that to attempt the shifting of change speed gearsof a power take-off driven unit while the truck is moving is quite aptto result in serious damage to the transmissions. Under such conditions,the disengagement of the main clutch of the truck will not obviate thedifiiculty, for since the power take-off is usually behind such clutch,

even though the latter be released the mixer Z drum will still be drivenfrom the road wheels of the truck.

In the case of mixer or agitator units equipped with the doubleclutch-reversing gear mechanism of the above mentioned Hilkemeierpatent, the

driving of the drum from the rear truck wheels may be prevented byshifting the clutch control lever of said mechanism to neutral, therebydisengaging both of the said clutches. This breaks the drive to the drumand stops rotation of the latter under all conditions in either theseparate engine drive or truck motor-power take-01f drive machines, andwith the drive thus relieved of the load imposed upon it by the drum,and its contents, change speed gears incorporated into the drive may beshifted with no appreciable danger of damage.

The shifting of the said reversing gear clutches may be accomplishedmanually, but whenever the truck is provided with a compressed airbraking system it is quite convenient and in most cases preferable tooperate said clutches by fluid pressure means. Because of the damagewhich may be occasioned should the change speed gears be shifted whileeither of the said clutches is engaged, it is desirable to provide meansfor positively insuring that both clutches are released before thechange speed gears can be shifted.

The power take-01f mechanisms referred to above are frequently mountedin different positions on different trucks, and furthermore, their driveshafts in some instances rotate in one direction and in some instancesin the opposite direction. The transmission mechanism for receivingpower from such take-offs should therefore be susceptible of variablearrangement to accommodate it to diiferently located take-offs, andsincethe direction of rotation of the mixing drum for mixing or fordischarging is always uniform, the transmission should be capable ofbeing arranged to deliver power uniformly in the same directionregardless of the direction of rotation of the input.

The present invention has for its principal object to provide arelatively simple power transmission and change speed gear unit forsupplying power to the mixing or agitating instrumentalities of atruck-mounted concrete mixer from the truck motor through a powertake-01f mechanism, which is substantially universally applicable toeffectively meet the above described conditions existing in the truckmixer field today, and which transmission and gear unit may be readilysubstituted for the usual separate engine of a standard truck mixer oragitator unit without requiring any changes in the usual construction ofsuch mixer or agitator unit.

A further object of the invention is to provide an improved yieldableshifting mechanism for the change speed gearing of the transmission andgear unit, which will also automatically serve as a detent for retainingthe gears in either shifted position.

A still further object of the invention is to provide aneffectiveinterlock between theheretofore used clutch shifting mechanismand the gear shifting mechanism of the present invention, whereby thelatter can be operated only when the clutches are disengaged and themixing drum is stationary.

With the above and other objects in view, which will appear as thedescription proceeds, the invention consists in the novel details ofconstruction, and in the novel combinations and arrangements 'of parts,more fully hereinafter disclosed and particularly pointed out in theappended claims.

Referring to the accompanying drawings forming a part of thisspecification, in which like reference characters designate like partsin all the views:

Figure 1 is a side elevational view, more or less diagrammatic, of awell known form of truck mounted concrete mixer equipped with compressedair operated controls for the reversing gear and clutch mechanism,illustratingthe application thereto of one form of power transmissionattachment constructed in accordance with the present invention, inplace of the usual separate engine;

Fig. 2 is an enlarged fragmentary elevational view, partly in section,as seen from the opposite side of the machine shown in Fig. 1;

Fig. 3 is a top plan view, partly broken away and in section, of thepresent transmission unit, as used in lieu of an independent engine inconnection with a double clutch-reversing-reduction unit of the typedisclosed in the said Hilkemeier Patent No. 2,243,035;

Fig. 4 is a longitudinal vertical sectional view through the presentunit, on a slightly larger scale, taken approximately on the planeindicated by the line 44 of Fig. 3, looking in the direction of thearrows; the change speed gearing being illustrated in the high speedposition:

Fig. 5 is a detail perspective view of the shifter cam element for thechange speed gearing;

Fig. 6 is a view similar to Fig. 4 of the change speed gearing, butillustrating the possible action of the yieldable shifting mechanism asthe change is made from high to low;

Fig. 7 is a transverse sectional View, taken approximately on the planeindicated b the line 11 of Fig. 6, looking in the direction of thearrows;

Fig. 8 is a partial cross sectional view, taken approximately on theplane indicated by the line 8-8 of Fig. 3, illustrating the essentialsof the clutch and brake actuating mechanism for the double clutchreversing apparatus of the said prior Hilkemeier patent, and showing thepresent interlock between such mechanism and the present change speedcontrols;

Fig. 9 is an elevational view of the parts shown in Fig. 8, as seen fromthe left of thesai'd figure;

Fig. 10 is a fragmentary transverse elevational view, as seen from theright of Fig. 2, illustrating the cab-located shifting lever and linkagefor the change speed gearing of the invention;

Fig. 11 is an elevational view, lookingv in the same direction as Fig.1, omitting the double clutch-reversing gear mechanism of the Hilkemeierpatent, but showing the essential features of the present inventionarranged to receive power from a take-off located further to the rear ofthe truck than in Fig. 1, and also illustrating a different positioningof the control lever for the double reversing clutches when the machineis not equipped with air operated controls therefor; and

Fig. 12 is a diagrammatic end view, illustrating two transversepositions which the power take off may occupy.

Referring more particularly to Figure 1, there is shown a truck mountedconcrete mixer unit of a well known commercial form, comprising a drummounted for rotation about a longitudinal horizontal axis in a unitframework l6, which latter is mounted upon and secured to the framemembers ll of a motor truck l8 which is supplied with the usual gasolineor Diesel motor within the hood I8 and with: the usual connections (notshown) for transmitting power therefrom to the rear wheels 20. Since themixer units are adapted to be mounted upon all makes of motor truck, theprecise construction of the latter may vary a'nd since it forms no partof. the present invention, it has not been illustrated in detail.

At the forward end of the frame I6. of the mixer unit there is mounted atransversely extending housing 2|, see Figs. 1, 2 and 3, which containsa double clutch-brake-reversing and reduction gear mechanism of the typeset forth in the said prior Hilkemeier Patent No. 2,243,035. The detailsof that mechanism have not been here illustrated, but it may be saidthatv the clutches are shifted to engage alternately by means of a lever22, rock shaft 23 and linkage 24 connected to a shifting, fork24'engagingwith a shifting collar 25.. The mechanism also in.- cludes abrake drum 26 having associated with it brake shoes 26 arranged to becontrolled through linkage 21 from the rock shaft 23,.whereby the brakewill be applied when both clutches are disengaged to bring the drum |'5to an immediate stop and hold it throughout the clutch disengagementperiod. The reduction gearing of this unit drives a shaft 28 journalledin atubular extension 25 of the housing 2|,.which shaft car'- ries asprocket 3|], diagrammatically shown in Fig. 12, which through a chain.3| and a" sprocket 32 mounted on the forward end of the drum-l5,transmits power to'the drum torotate it.

As best shown in Figs. 4 and 6, the housing 2| is provided with atransverse partition wall 35 dividing it into two chambers 36 and 31, inthe former of which the double lclutchreversing-reduction gear mechanismjust referred to is mounted, while as above stated, the chamber 31 insome instances of separate engine drive may house a mainclutch; Thewalls of the housing surrounding the chamber 31' are expanded asindicated at 38 (Figs. 3' and 7) to a substantially bellshape, and theend of the housing is provided with a circular flange 39 which hasheretofore been bolted to the'fly-wheel' housing' of the separateengine.

With the'use of the double clutch arrangement of the Hilkemeierapplication, or with the elimination of the separate engine, a clutchwithin the chamber 31 is not required, leaving this chamber availablefor other purposes, and the present invention contemplates a powertransmission attachment for truck motor drive purposes which includes achang speed gear mechanism which may be introduced into and housedwithin the chamber 31 as it stands. The flange 39 of the housing 2|affords a ready means for the attachment-thereto of a plate 40 whichserves as a support for the truck motor drive unit now to be described.

As the standard power take-offs for truck motors usually embody a driveshaft the axis of which is longitudinal of the truck, i. e., parallel tothe propeller shaft of the latter, and since the housing 2| and itsreduction gearing are normally mounted for the reception of power from atransversely mounted separate engine, the present attachment for truckmotor drive preferably incorporates as a part thereof mechanism, suchfor example as bevel gearing, for transmitting power at right angles,from an axis longitudinal of the truck to an axis transverse thereof,said power after passing through the change speed mechanism of theattachment in chamber 31 being delivered to the reduction gearing and/orother mechanism in chamber 36, and transmitted by it to the drum IS inthe usual manner.

To this end, the plate 40, which as above inclicated is arranged to besecured tothe flange 39 of housing 2| in lieu of the fly-wheel housingof the separate engine, has secured to it by bolts il one end of anannular casing 42, the other end of which is closed by an end plate 43',carrying a ball or other bearing 44 for journalling one end of a shaft45, see Figs. 3 and 4. The axis of the casing 42 and shaft 45 istransverse to the longitudinal axis of the mixer unit and of the truckon which it is mounted, and carried by and extending at right anglesfrom the said casing, with its axis in substantial parallelism with saidlongitudinal axis of the truck and mixer unit, is a tubular' extension4B in which is journaled, as by ball bearings 41, an input shaft 48.This shaft carries at its outer end a sprocket or pulley 49 forengagement by a chain or belt 50, see-Figs. 1 and 2, which is adapted tobe driven by any suitable power take-offmechanism 5| deriving power fromthe truck motor in any usual manner.

The inner end of the shaft 43 carries a bevel gear 55 which meshes witha companion gear 56 carried: by the shaft 45, see Figs; 3 and 4. Sinceas above indicated, the drive shaft of the power take-off 5| in somecases'rotates in one direction and in some cases in the oppositedirection, the gear 56 will be mounted on the shaft 45 in assemblyeither in the position shownin full lines or the position shown inbroken lines in these figures, depending upon thedirection'of rotationof the input shaft 48, whereby the shaft 45 will always be driven in thesame direction.

The inner end of the shaft 45 is received in and keyed to the hub 60'ofa gear 6| constituting a portion of the'change'speed mechanism of theattachment, the said hub' being journalled in a ballor other bearing 62mounted inthe attaching and supporting endplate 40; The gear 6| isrecessed internally for the" reception of a-ball bearingGS which:journals one end of theoutput shaft 64 of the unit, theother end ofwhich is journaled in a ball or other bearing 65 mounted in a bearinghousing member 66 which is slidably received in an aperture 61 withwhich the intermediate partition wall 35 of housing 2| is normallyprovided. Beyond the bearing 65 the output shaft 64 carries a bevelpinion 68 arranged to mesh with one or more bevel gears 69 of thereversing and/or reduction gear unit in cham ber 36.

The change speed gearmechanism of the attachment unit is preferably ofthe constant mesh spur gear type, in which the connection between thedriving and driven elements for the different speeds is accomplished bya sliding clutch member 10. This member is provided with internal teethH, see Fig. '7, equal in number and complementary to the teeth of thegear BI, and the said member is slidably mounted upon a collar 72, keyedto an intermediate portion of the output shaft 64 and provided withexternal teeth 13,

also equal in number and complementary to the teeth of the gear 6|, withwhich it is axially alined. Thus, when the teeth of the gear 6i arecircumferentially alined with the teeth of the collar 12, the clutchmember 19 may be moved into overlapping power transmitting engagementwith the two, as illustrated in Fig. 4, thus providing a direct drivebetween the shafts 45 and 64 through the hub 60, gear 6|, clutch member10 and collar 12, as will be readily understood.

To provide a different and preferably a lower speed drive for the shaft64, a countershaft I5 is mounted below the shaft 64, one end thereofbeing received in'the plate 40 and the other end being received by anextension 16 of the bearing housing member 66, as will be clear fromFigs. 4 and 6. This shaft does not Irotate, being restrained by ash'oulder 11 on the last mentioned end thereof which longitudinallyslidably engages 9. lug 78 formed on the intermediate partition wall 35.Journaled upon the countershaft 15 as by roller bearings 19 is a gearset comprising a sleeve 80 having at one end a gear 8| in constant meshwith the gear BI, and at its other-end a smaller gear 82 which is inconstant mesh with a gear 83 which is freely journaled upon the shaft64. The gear 83, which is of larger diameter than the gear 6|, has a hub84 between itself and the clutch collar 12, which hub is provided withexternal teeth 85, equal in number and complementary to the teeth on themembers 19 and 12. It thus results that when the teeth 85 and 13 are incomplementary circumferential disposition the clutch member 19 may heslid toward the left from the position shown in Fig. 4 to one in whichit provides a driving engagement between the gear 83 and the collar 72,whereupon the drive will be from shaft 45 through hub 60, gear 6|, gear8!, sleeve 86, gear 82, gear 83, clutch member 10 and collar 12 to shaft64. Since in the embodiment shown the gear 8| is larger than the gear6|, and the gear 83 is larger than the gear 82, the output shaft 64 willunder these conditions be driven at a less speed than that of the shaft45. In either the direct or the reduced speed drives, however, the shaft64 will be driven in the same direction.

For shifting the clutch member 10, the following mechanism is provided:The said member is I provided with an exterior circumferential groove 88in which is received a substantially semi-circular shifting yoke 89,there being a running fit between the two whereby the clutch member mayfreely rotate within the yoke. The latter carries a pair ofdiametrically opposed trunnions 90 which are received in slots 9|formed; in the ends of the arms 92 of a shifting fork 93 which ispivotallymounted on a pin or shaft 94. The said shaft is carried by apair of ears 95, here shown as formed integrally witha cap plate ormember 96 which is secured on the top of housing 2| above the chamber31. The ears 95 extend downwardly from the cap plate 96 through anopening 91 which is normally present'in the top wall of housing 2|. p I-:v

The shifting fork 93 .is provided with a rigid upstanding lug 98which=is provided with a pair of transversely spaced apertures 99therethrough, see Fig. 7. The said fork is mounted medially on the pin94 and to'either side thereof, between the fork hub and the--ears- 95,there is jour-v naled an arm I00. As best seen in Fig. 7, these arms areoffset inwardly so that their upper ends are in line, and the said upperends are provided with pads Hit, the inner faces of which embrace asquare cam member I92 which is rigidly eccentrically carried by a hubI93. The cap: plate 96 is crowned as at I95, and a rock shaft !06 isjournaled in a bearing boss I91 extending from the said crown, the hubI93 of the cam member I02 being rigidly secured to the inner end of thesaid rock shaft I06.

As viewed in Figs. 4 and 6, the arms I60 are disposed one to either sideof the lug 98 of the shifting fork, which they overlap and normallycontact, and each arm carries a bolt H9 which freely passes through oneof the apertures 99 in the said lug. A helical compression spring l !lsurrounds each bolt H0 beyond the lug 98, the inner end of each springbearing against: an outer face of the lug, while the inner ends of saidspringsseatiupon washers H2 backed by adjust ment nuts H3 threaded 0nthe freeends of the respective bolts H9. The springs III are preloadedthrough adjustment of the nuts 13 to an extent sufficient topartiallyrestrain free movement between the arms I00 and the lug 99.

As will be clear from Fig; 4, when the clutch member 10 is in fullymeshed power transmitting position as shown, the inner flat faces of thepads [0| of the said arms are in flat engagement with two opposite facesof the square cam member I02, which is arcuately displaced some 25 ormore from the vertical plane of the axis of the rock shaft I06. In thecourse of a normal manual shift of the cam from this Fig. '4 position tothat shown in Fig. 6, as the cam reaches the said vertical plane,instead of having two opposed faces presented to the complementary facesof the pads I91, it' will have two opposite corners in engagementtherewith, and since the diagonal of the square is longer than a sidethereof, the arms I90 will have been spread somewhat against thepressure of the springs l i I. When the cam passes the vertical plane itbegins topresent its other two opposed faces to the inner faces of thepads 10! and since the springs HI are always tending to produce a flatcontact between the pad and cam faces, they will tend to facilitate thecompletion of the shift.

When, as sometimes happens in the course of a shift, the teeth of thegear 6! of the hub 84 are not in meshing alinement with'the teeth "H ofthe clutch member 10, the sliding movement of the said member 10 will betemporarily arrested until such alinement results from the rotation ofthe gears 83 and 6|. This condition is illustrated in Fig. 6 duringashift from high to low speed, and it will be observed that when it doesoccur, motion of the rock shaft I06, and cam member I02 is not arrestedbut continues to the normal limits thereof. This is permitted by theyielding of one of the arms I00, as for example the right hand one inFig. 6, against the action of its spring III, which is thus furthercompressed, as shown. The pressure exerted by this spring against thelug 98 is tending to move the shifting fork 93 in a clockwise direction,as viewed in the said figure, which is the direction necessary tocomplete the shift, and as soon as the teeth 14 and 85 are in meshingalinement, the said spring pressure acts to accomplish such meshing witha snap action. The ends of the intermeshing clutch teeth 85 and I4, andof the gear 6I may be beveled in accordance with common practice tofacilitate such meshing.

The spring pressed arms I also serve as detents for retaining the clutchmember #0 in either fully meshed position. For example, in the highposition illustrated in Fig. 4, any tendency of the clutch member 70 toshift axially in either direction from the position shown tends toproduce an arcuate movement of the cam I02 and shaft I06. However, suchmovement would destroy the flat face to face contact between the cam andthe pads ml and tend to bring the cam corners into engagement with thesaid pad faces, with a consequent spreading of the arms I00, which ofcourse is resisted by the springs III. It therefore results that while ashift from either speed to the other may be freely accomplished throughthe application of suflicient force, manual or otherwise, to the rockshaft I06 to overcome the preloading of the springs III', accidental orunintentional shifting is'preventedthrough the detent action justdescribed.

When the present unit is employed with the double clutch-reversing gearmechanism of the said Hilkemeier application, it is preferred to providean interlock between the two, whereby it is impossible to shift theclutch member except when both clutches of the said Hilkemeier mechanismare disengaged, v One example of such interlock is illustrated in Figs.3, '7, 8 and 9. In this form, the mechanism comprises a rod II5 havingan angularly disposed end portion II6 which serves as a pivotalconnection between the link 2! and the rock arm 27* of the brake controllinkage 21. The free end of the rod H5 is freely slidable in'a blockII'I which is pivotally carried by the upper end of an arm I It, thelower end of which is rigidly carried by one end of a rock shaft 9journaled in a bearing tube I20 mounted by a bracket I2I which issecured on the top surface of the housing 2|. A compression spring I25surrounds the rod I between one side of the block II! and a stop washerI26 carried by the rod, and urges the said block and the arm I I8 towardthe full line position shown in Fig. 8; An adjustable stop, here shownin the form of lock nuts I21 threaded upon the rod H5, is provided tothe other side of block 1, the said stop being so positioned on the rodas to provide for a certain amount of lost motion movement of the rod inthe block.

The other end of the rock shaft I I9 rigidly carries a dog I30,overlying the operating rock shaft I06 of the change speed gearmechanism above described, and oscillatable in the plane of the axis ofsaid shaft I06. The free end of the said dog I30 is receivable in one orthe other of the two notches or recesses I3I and I32 provided in alocking plate I33 which is rigidly carried by the rock shaft I06.

The operation of the interlocking mechanism just described is asfollows: With the various parts in the full line positions shown inFigs. 3, 8 and 9, the control lever 22 of the double clutch-reversingmechanism is moved to neutral position, thereby moving the rock shaft 23in a clockwise direction, as viewed in Fig. 8, and through the clutchcontrol linkage 24 and shifting collar 25 throwing out the engagedclutch of the said mechanism. The same movement of the shaft 23 movesthe link 21 of the brake control linkage 2? from the full line positionshown in the said figure to the horizontal broken line position showntherein, thereby swinging the arm Zl to its broken line position andthus applying the brake shoes to the brake drum 26.

This movement of the link 21 and arm 2'I'l draws the rod II5 toward theright, as viewed in said Fig. 8, and during the first part of thismovement the rod slides freely in the block 'I IT, with the compressionspring I25 expanding and maintaining the said block, the arm H8, therock shaft I I9 and the dog I30 in the full line positions. However, thestop I2! is so positioned upon the rod II5 that before the link 21* andarm 2? complete their movement totheir broken line positions, the saidstop engages the block I I1, whereupon the further movement of the rodII5 serves to draw the arm II8 to its broken line position shown in Fig.8, thereby rocking the shaft H9 and lifting the dog I30 to its brokenline position, disengaging its free end from the notch 32- in thelocking plate I33. The operating rock" shaft I06 of the change speedgearing is now free to move and may be rocked to effect the shiftof theclutch member I0 from engagement with the gear 6| to engagement with theteeth of gear 'hub84'. This movement of the shaft I06 brings the notchI3I into alinement with the dog'l30.

When the shift has been completed, the clutch control lever 22 may beeither returned to the position .from which it was moved, to re-engagethe clutch of the Hilkemeier mechanism which had been previouslyengaged, thereby continuing the rotation of the drum I5 in the samedirection but at a lcwerspeed, or the said lever 22 and rock shaft 23may be moved further in a clockwise direction, as viewed in Fig. 8, toengage the other Hilkemeier: clutch, thereby reversing the drumrotation. In the first instance the link 27 of the brake control linkagewill be returned to its full line position, while in the second case thesaid link will be moved to the dotted line position shown in saidfigure, but in either event the effect will be to return the arm 2I' andthe pivot extension I I6 of rod II5 to the full line positions showntherein. The movement of the rod I I5 toward the left will return thearm [I8 and the-dogl30 to their full line positions,

the said dog however, engaging in the notch I3I of the locking plate I33and again locking the rock shaft I00 against movement. The dog will seatin the notch prior to the completion of the movement of the rod 5, andthe latter part of such movement will serve to again load the springI25, as will be readily understood. The same sequence of movements willof course take place when it is desired to again shift the change speedgearingv to high or direct drive.

Reference was made above to the varying locations of the power take-offsin different trucks,

and in Fig. 12 there is diagrammatically indicated in broken anddotted-lines respectively, two possible transverse locations of thetake-off I. In addition to such possible variations in the transverselocation of the take-off, its longitudinal relation to the powertransmission mechanism of the mixer unit may also vary. That is to say,instead of being located as in Fig. 1 so that the drive chain or belt 50may run up in front of the power transmission unit, the take-off may insome instances be positioned relatively further toward the rear of themixer unit, as indicated in Fig. 11. When such a location isencountered, by removing the bolts 4! and bodily rotating the casing 42about its axis through an angle of 180 to the position indicated inbroken lines in Fig. 3, and then replacing the bolts M, the input shaft43 of the unit may be caused to extend rearwardly instead of for- Wardlywith respect to the unit, as shown in Fig. 11, and the drive chain 50may be brought up between the unit and the drum. It will thus be seenthat the transmission unit of the present invention is well adapted forsubstantially universal use regardless of the position of the powertake-off 5I.

Shims I are preferably provided between the plate and the flange 39 ofhousing 2i, and since the bearing housing 60 is slidable in the aperture01 in the wall 35, by varying the number of shims employed, a propermeshing of the teeth of pinion 68 and gears 69 without backlash may besecured.

While in some instances the rock shaft I06 may be extended beyond thehub of the locking speed gearing extends upwardly through the floor ofthe truck cab MI in front of the seat I42, being rigidly carried by arock shaft I43 mounted in suitable bearings I44. The rear end of thesaid shaft rigidly carries an arm I45 which is connected by an upwardlyextending link I46 to the locking plate I33. As will be readilyunderstood, by shifting the lever I40 between the two positionsindicated in Fig. 10, the rock shaft I06 may be actuated to shift thechange speed gear mechanism from high to i low and vice versa, asdesired.

As previously indicated, the machine shown in Fig. 1 is equipped withcompressed air operated mechanism for controlling the reversing clutchesof the prior Hilkemeier application. While such so mechanism in itselfconstitutes no part of the present invention, it may be brieflydescribed as comprising a fluid pressure operated actuator or motivedevice I50 having an actuator arm or lever I5i connected by a link I52to the lever 22 which controls the reversing clutches. The motive deviceI50 is controlled by suitable valves contained within a housing I53,which valves are actuated by means of a lever I54. A link I55 connectsthis lever with a hand lever I56 mounted at the rear of the machine,whereby the rotation of the drum, and the direction thereof, may becontrolled from this point. Such movements of the drum may also becontrolled from the truck cab MI by means of a push-pull rod I51, whichis connected through rock levers I58 and I59, and links I60 and IBI, tothe valve control arm I54. Obviously, by extending the rock shaft I43 tothe rear of the machine, control of the change speed gearing-may also beeffected from that point if desired.

When the machine is equipped with fluid pressure actuated controls asjust described, it is preferred to mount the lever 22 on the rock shaft23 substantially as shown in Fig. 1, to move from one side to the otherof a'vertical plane. However, in cases where fluid pressure controls arenot used and the shifting of the reversing clutches is accomplishedmanually, it is preferable to mount the lever 22 at approximately rightangles to the position shown in Fig. 1, as indicated in broken lines inFig. 11. When so mounted the said lever moves from one side to the otherof a substantially horizontal plane, and

extends forwardly beside the cab MI in a position in which it may bereadily manually actuated by the operator without leaving the cab. Thesaid lever may be provided with a suitable counterweight 22" toneutralize its tendency to shift the clutches.

The shaft 45 may be extended beyond the end plate 43 of the casing 42and be utilized for furnishing power to one or more accessoryinstrumentalities of the mixer unit, such for example, as a water pumpfor supplying water to the drum I5.

While one form of the invention. has been illustrated and described, itwill be obvious that those skilled in the art may vary the precisedetails of construction and arrangement of parts without departing fromthe spirit of the inventicn, and therefore it is not wished to belimitedto the above disclosure, except as may be required by the followingclaims.

What is claimed is:

1. A truck-motor-drive power transmission unit for substantiallyuniversal application to truck-mounted concrete mixer units in lieu ofthe usual separate engine, which mixer units are provided with areduction gearing and a housing therefor, having a plurality of chambersin one of which said reduction gearing is located, said transmissionunit comprising a member arranged to be secured to the end of said gearhousing in the place of the fly-wheel casing of the usual separateengine; a jchange-speed mechanism disposed transversely of the truck andmixer unit, arranged to be received within another chamber of saidreduction gear housing and to transmit power to said reduction gearing,said mechanism being supported at least in part by said member; alongitudinally disposed input shaft supported by said member exterior ofsaid housing, arranged to receive power from the truck motor through apower take-off mechanism; and angular-motion-transmitting means arrangedto transmit the power from said input shaft to said change-speedmechanism.

2. A truck-motor-drive power transmission unit for substantiallyuniversal application to truck-mounted concrete mixer units in lieu ofthe usual separate engine, which mixer units are provided with areduction gearing and a housing therefor having a plurali of chambers inone of which said reduction gearing is located, said transmission unitcomprising a plate arranged to be secured to the end of said gearhousing in the place of the fiy-wheel casing of said separate engine; achange-speed mechanism arrangedto be disposed transversely of the truckand mixer unit Within another of said chambers, said mechanism beingsupported at least in part by said plate; a casing supported by saidplate exteriorly of said housing and having a longitudinal extension; aninput shaft journaled in said extension, arranged to receive power fromthe truck motor through a power take-off mechanism; andangular-motion-transmitting means within said casing arranged totransmit the power from the longitudinally disposed input shaft to thetransversely disposed change-speed mechanism; said casing being arrangedto be positioned with said extension and input shaft disposed eitherforwardly or rearwardly to accommodate different locations of the powertake-off mechanism.

3. A truck-motor-drive power transmission unit for substantiallyuniversal application to truck-mounted concrete mixer units in lieu ofthe usual separate engine, which mixer units are provided with areduction gearing and a housing therefor having a plurality of chambersin one of which said reduction gearing is located, said transmissionunit comprising a plate arranged to be secured to the end of said gearhousing in place of the fly-wheel casing of said separate engine; achange-speed mechanism arranged to be disposed transversely of the truckand mixer unit witlr'n another of said housing chambers, said mechanismbeing supported at least in part by said plate; a casing supported bysaid plate exteriorly of said housing and having an extension disposedlongitudinally of the mixer unit, said casing being arranged to bepositioned with said extension disposed either forwardly or rearwardlywith respect thereto to accommodate different locations of a powertake-ofi'mechanism; an input shaft journaled in said extension,

arranged to receive power from the truck motor through such take-offmechanism; and angularmotion-transmitting means within said casingincluding a pair of bevel gears arranged to transmit the power from saidinput shaft to said change-speed mechanism, one of said bevel gearsbeing arranged to be mounted at either side of the other, whereby toprovide a uniform-direction drive of said change-speed mechanism frominput shafts rotating in one direction or the other.

4. A truck-motor-drive power transmission unit for substantiallyuniversal application to truck-mounted concrete mixer units in lieu ofthe usual separate engine, which mixer units are provided with areduction gearing and a housing therefor having a partition walldividing it into a pair of chambers in one of which said reductiongearing is located, said transmission unit comprising a plate arrangedto be secured to the end of said gear housing in place of the fly-wheelcasing of said separate engine; a change-speed mechanism arranged to bedisposed transversely of the truck and mixer unit Within the other ofsaid'housing chambers and to transmit power at selective speeds to saidreduction gearing, said mechanism being supported in part by said plateand arranged to be slidably supported in part by the partition wall ofsaid housing; and bevel gear mechanism carried by said plate exteriorlyof said housing, including an input shaft disposed longitudinally of thetruck and arranged to receive power from the truck motor, said powerbeing transmitted by the bevel gearing to said transversely disposedchange-speed mechanism.

CHARLES F. BALL. LOUIS G. HILKEMEIER.

